FMF - Friends of Minerals Forum, discussion and message board

[Kowen]

Can I please get advice on how to clean and polish this piece of calcite? Thanks!

[James Catmur]

It looks very heavily weathered to me. If you want to polish it maybe head to a polished stones forum, as we deal with natural specimens on this forum. I doubt you could tumble it but maybe you could polish it? Sorry not my area of expertise.

[SteveB]

Something I do is use a small plastic basket with specimens in it. I spray with an organic degreaser product and let sit for a day or two in the sink for it to work into cracks, etc. Then I pop the basket in my dishwasher ready for the next run. Organic degreaser is gentle at lifting dirt and safe for dishwasher and wastewater. Stronger cleaners often have chemicals to clean calcium or iron stains and could damage your specimen, and using a basket allows the water spray to reach all parts of specimen and it contain pieces that break off if it was fragile. Pretty simple really but calcite is of course calcium so many cleaning products will eat into it so don't use on nice clear calcite crystals, but it works great to clean dirt from those rocks you dug out of the ground. While it won't polish, it's a simple easy first step that works well to clean out those cracks full of dirt.

[Matt_Zukowski]

Are you sure it is calcite? Have you done a fizz test and hardness? I ask because although it certainly could be a carbonate, it looks kind of like chert.